JP2010516509A - Droplet size in inkjet printing - Google Patents

Abstract

A printer control unit (3) for controlling the size of droplets ejected by the nozzles (8) of the print head in an ink jet printer is described. The control unit (3) receives information relating to the image printed by the printer, for example from the raster image processor (5). Information relating to the image printed by the printer includes droplet size information relating to the size of the droplets ejected from the nozzles and required to print the image. Print parameter information for printing an image is determined based on the received droplet size information. The print parameter information includes information used to set the printer so that the droplets ejected by the nozzles during printing of the image have the required droplet size.
[Selection] Figure 1

Description

  The present invention relates to ink jet printing. The aspects of the invention described herein relate to a method and apparatus for controlling droplet size in an ink jet printer. The invention is particularly utilized in drop on demand ink jet printers.

  In an ink jet printing process, a large number of droplets, such as ink droplets, are deposited on the surface of a substrate in a fixed pattern to form the required image. Ink drops are typically ejected from a number of nozzles of an ink jet print head. A typical printer includes a plurality of print heads in a print head array. In general, during a printing procedure in which the entire requested image is printed on a substrate, a relative movement is required between the printhead array and the substrate.

  Various types of print heads are available that eject droplets of printing material (eg, ink) using methods well known in the art.

  Most commercial and industrial inkjet printers use a piezoelectric material to eject ink drops from printhead nozzles. In such a print head, each print nozzle is connected to a channel filled with ink associated with a piezoelectric material. When an electric pulse is input to the piezoelectric material, the size or shape of the piezoelectric material changes, so that a pressure pulse is generated in the ink in the channel, and an ink droplet is ejected from the nozzle.

  In a thermal ink jet print head, a heating element is disposed adjacent to an ink channel (passage). The electric pulse input to the heating element generates bubbles in the ink channel, and as a result, ink droplets are ejected from the nozzles.

  In order to obtain a high-quality image, it is necessary to control the amount of ink ejected as droplets. One of the ways in which droplet sizes can be varied is to change the pulse (printing pulse) input to eject ink. In particular, the input voltage and pulse width are selected so that the required amount of ink is ejected in each droplet.

  The printer parameters and settings (eg, voltage and pulse width) required to obtain a particular droplet size in one type of printer will be different from those in other printers, and the print head used and The type of ink will also be a factor. In general, the pulse amplitude and pulse width are set to obtain a standard droplet size based on information about the incoming pulses provided by the printhead manufacturer.

  Accordingly, the configuration of the print head is generally set to print droplets with a standard droplet size. In many cases, each drop is set to have an ink mass of about 30 ng (nanogram). This is approximately equal to an ink volume of 30 picoliters. Drop mass is generally easier to measure than actual drop volume and is a convenient way to measure drop size.

  For various applications, a drop size of about 30 ng is acceptable because it can provide reasonable print quality at an acceptable printing speed.

  However, it may be desirable to print using droplets of other sizes. For example, smaller droplets can give better image quality, especially in light colors, with improved print resolution and sharper image edges in addition to a smooth finish.

  However, it is generally necessary to deposit a certain amount of ink on the substrate to form an image, so if each drop volume is reduced, it will be more for the printed image. It will generally be necessary for the droplets to be deposited. For example, if the droplet size is halved, even when printing the same image, twice as many droplets need to be ejected when printing with small droplets compared to when using large droplets. there will be.

  Therefore, the data provided to the print head to apply 30 ng droplets may not be appropriate for printing using 15 ng droplets. Therefore, insufficient droplets will be deposited to form an image, so it is not possible to simply change the printer configuration to apply small droplets. Similarly, if a large drop is substituted while using the same image data, the substrate will overflow with ink. Furthermore, changing the droplet size parameter is not easy. The relationship between pulse voltage, pulse width, and other factors is not simple.

  The present invention seeks to address the problems identified in the prior art described above.

  Accordingly, a first aspect of the present invention provides a printer control unit for controlling the size of droplets ejected by nozzles of a print head in an ink jet printer, and prints an image ejected from the nozzles. Means for receiving information relating to an image to be printed by a printer, including droplet size information relating to the size of the droplets required to, and for printing said image based on said received droplet size information Means for determining the printing parameter information, wherein the printing parameter information comprises information used to set the printer such that the droplets ejected by the nozzles during printing of the image have the required droplet size. A printer control unit including the printer control unit.

  Preferably, the unit further comprises means for sending the print parameter information to the printer and / or a component of the printer to configure the printer to print the image using the droplet size. Including. The unit may be part of the printer itself.

  Accordingly, in a preferred form of the invention, the printer is set to print an image with a predetermined droplet size associated with the image information. In a particularly preferred embodiment, the entire image is printed using this predetermined droplet size. Desirably, all droplets ejected from the nozzles during image printing have the required droplet size, ie the same size. Thus, in the preferred embodiment, the droplet size setting is the same throughout the printing process of printing the image. Preferably, during image printing, the nozzles eject only droplets of that droplet size. It is understood that due to variations in nozzle performance while printing is performed, the size of the droplets ejected by the nozzles will usually have some variation in actual size.

  It will be appreciated that the image referred to is preferably printed during a single printing operation or printing operation. Image data for printing an image is generally included in one image file. It is understood that the images referred to herein may actually be part of a larger image or part of a composite image that is composed of several individual images arranged separately.

  The print parameter information is preferably sent directly to the printer components to change the printer settings as needed. The transmitted information may include image data for executing image printing, or the image information may be transmitted separately.

  Preferably, the means for determining the printing parameter information includes means for retrieving from the memory predetermined printing parameter information related to the required droplet size.

  This memory may be part of the control unit. In a preferred configuration, the print parameter information includes information regarding printer settings. Preferably, the print parameter information includes information about printer setup and / or overall operation of the component rather than data about the image to be printed. Therefore, preferably, the printing parameter information includes printer parameters and / or setting information. The information may include a plurality of groups of print parameter setting values, each group including a printer setting for printing using a particular droplet size. Different parameters may be stored separately in memory or as a group of parameters associated with a particular droplet size. Information may be stored in a look-up table. Accordingly, the memory may include printer setting information regarding a plurality of different droplet sizes.

  Accordingly, the apparatus may include means for determining from the memory information relating to a plurality of printer settings relating to droplet size.

  Alternatively, or in addition, some or all printing parameter information may be calculated depending on the specific required droplet size. Information may be calculated on-the-fly.

  Preferably, the means for determining printing parameter information includes means for calculating printer settings according to droplet size.

  The printer setting may be calculated using a predetermined formula. In this way, printer settings can be calculated over a range of droplet sizes. However, in some cases this option may be less desirable because the result of the calculation is less accurate than the measured data points.

  Preferably, the print parameter information includes information regarding printer settings.

  Desirably, the print parameter information includes information about several parameters of the printer that are set to obtain the required droplet size during image printing.

  The print parameter information may include information related to a print pulse for ejecting droplets from the print head nozzle.

  The information may include, for example, information regarding frequency, amplitude, pulse width, or other characteristics of the print pulse.

  The information may relate to the entire print head, a group of print heads, several nozzles of one or more print heads, or a print pulse for a single print head nozzle. In some configurations, the nozzles may be grouped together to be activated using a single pulse or some type of pulse. For example, nozzles for applying a specific color ink could be grouped together. The grouping of nozzles is preferably determined based on the amount of control required for droplet size. For example, if the printer configuration allows several different nozzles to be used to print a particular part of the image during printing, precise control of the droplet size of each nozzle can Compared to a configuration in which only one or a few nozzles are used to print the image, it will not be significant. In the latter case, the variation in droplet size of a particular nozzle group will add significant visual artefacts to the printed image.

  The information may include information regarding the pulse voltage. In some configurations, based on the droplet size, the voltage used will affect the velocity of the ejected droplets, and problems may occur if small droplets are ejected at a low velocity. It has been found useful to change the voltage.

  The information may include information regarding the printing pulse frequency. The frequency used is based in some embodiments on the droplet mass, the pulse width used, and other factors.

  The information may include information related to other printer settings, such as the relative speed of movement of the print head and the substrate on which the image is printed. If the amplitude of the print pulse is changed and the print droplet size is changed, the time it takes for the droplets to move from the print head to the substrate can be changed, especially when the image is printed bi-directionally (bi This must be taken into account when printing using -directional printing) technology.

  Devices for monitoring the ink level of the print head often use droplet size information to determine the amount of ink used. For example, as the droplet size decreases, it will take more time for the ink to be used up by the droplet. Accordingly, the print parameter information preferably also includes information regarding the settings of the ink monitoring device.

  The print parameter information may include information regarding the temperature at which the print head operates. In some configurations, the print head may include a heater that is used to obtain a desired ink temperature in the print head.

  The print parameter information may be determined based on the type of print head used, the type of ink used, and / or the color of ink used, and / or other factors.

  Preferably, the unit is adapted to control the size of the droplets ejected by a plurality of nozzles, and the printing parameter information for setting up the printer includes the required droplets during printing of the image. Contains information used to set the plurality of nozzles to eject droplets having a size. Accordingly, a group of nozzles may be set for each group to print droplets with a specific droplet size. For example, a print head or group of print heads may be set to print with a specific droplet size. For example, a print head for a particular color ink may be set to print with a specific drop size, and different drop sizes may be set for other print heads or groups of print heads. good.

  The control unit may be adapted to control the size of the droplets ejected by the first nozzle and the second nozzle in the inkjet printer, and droplet size information is ejected to print the image. Information about two required sizes for a droplet, wherein the printing parameter information includes a droplet ejected by a first nozzle during printing of the image having a first required droplet size; And including information used to set the printer so that the droplet ejected by the second nozzle has a second required droplet size. Thus, different nozzles or groups of nozzles can be set up to print different sized droplets. For example, the various print heads of a printer could be set up to print droplets of various sizes. Thus, some print heads may print small droplets while other print heads may print large droplets. In this way, portions of the image that require small droplets (eg, light-colored portions) can be printed using small droplets, while other portions (eg, wide-area fills or sharp images) The edge portion) can be printed using large droplets. In these configurations, it is still desirable for each nozzle or group of nozzles to print droplets with only one droplet size during the entire printing operation.

  A particularly important feature of the present embodiment is that printer settings can be set automatically to print an image based on information received regarding droplet size.

  Preferably, the control unit includes means for determining the printer settings used to print the previous image.

  Even when the printer settings are changed automatically, there is time associated with changing the settings. Therefore, it would be advantageous to avoid changing settings unnecessarily. Accordingly, preferably the control unit includes means for determining whether the printer settings are already set to the desired values for printing with the required droplet size for the next image. If set to the required droplet size for the next image, in some configurations no further changes are required or the number of changes may be reduced.

  Preferably, the control unit includes means for determining the printer settings used to print the previous image, and means for comparing the received droplet size information with the previous image droplet size information.

  Information regarding the previous droplet size may be stored in memory. If the comparison indicates that the droplet size information for the previous image is similar to that for the current image, the printer is probably already set to print at the required droplet size. So no further action on changing printer settings is required.

  Alternatively, one or more print parameter settings can be determined to assess the droplet size that is the basis for the printer's current settings, and the determination of whether further changes are needed Is done.

  Alternatively, the printer control unit can be configured to store information relating to the settings of the previously printed image. This information can be compared with the information of the current image to be printed to determine if a setting change is necessary.

  Preferably, the control unit is designed to receive droplet size information from a raster image processor. Droplet size information may not be received directly from the RIP, but will be subject to additional processing first.

  Since the number of droplets printed is generally dependent on the size of the ejected droplets, the size of the ejected droplets often needs to be determined at the RIP (raster image processing) stage. Thus, preferably the control unit receives both bitmap image information from the RIP and information regarding the droplet size for which the image information was processed.

  The present invention also provides an apparatus comprising a control unit and raster image processor means as described herein. Raster image processors will generally be incorporated into the software.

  While RIP can be performed at the printer control unit, in many embodiments it is desirable that RIP be performed at a separate special RIP.

  Desirably, the RIP is adapted to send information about the image to be printed to the control unit, the information being a droplet size related to the size of the droplets ejected by the print head to print the image. It is characterized by including information.

  Preferably, the image information includes a job file in which droplet size information is incorporated. A print job file basically consists of one print head for each required print resolution, image size, original image name, processing date, processing parameters used, carriage position for each pass, and engine pass. It consists of some header information such as a series of image fragments arranged so that there are fragments. The droplet size information may be included in the file header.

  As indicated above, the RIP and control unit can be combined, and the output of the RIP will effectively be a printer setting that will be sent directly to the printer. However, in this case, the RIP will need to be specialized for a specific printer or a specific type of printer that will reduce the flexibility of the system. In some preferred embodiments, the RIP is separate from the printer driver that includes a printer control unit that determines printer settings. This means that even if the printers have different voltage / pulse amplitude sensitivities, one job file can be executed by physically different printers and the same result can be obtained. Similarly, even if the sensitivity of the two print heads is different, the job file will give consistent results after the individual print heads are replaced.

  Preferably, it includes means for accepting an input regarding droplet size for the printed image to the RIP.

  This information may be input by the user from, for example, a drop-down list. As indicated above, in some configurations it may be desirable for the droplet size information to relate to one of a plurality of separate droplet sizes. The droplet size selected by the user may be identified quantitatively (eg, 15 ng, 22 ng, 30 ng) or qualitatively (eg, small, medium, large).

  Preferably, the arrangement includes means for determining that droplet size information is not available and means for determining information regarding default settings for printing an image.

  If the specific droplet size for a particular image print has not been determined, it will be printed using the “normal” droplet size, for example, rather than using the previously used droplet size setting This may be desirable for images. Thus, if the control unit does not receive the droplet size information along with the image information, or if the RIP does not obtain the droplet size information, the device sets the printer as the default for image printing. It is desirable to be adapted so.

  Preferably, the apparatus further includes a printer and a print head configured to receive print parameter information from the control unit.

  The present invention is further configured to output information relating to the image to be printed, the information including droplet size information relating to the size of the droplets ejected by the print head to print the image. A raster image processor is provided that is preferably used in conjunction with the control unit described herein.

  The present invention further preferably includes bitmap information relating to an image printed using an inkjet printer, and further information relating to the droplet size of the droplets ejected by the printer to print the image. Serve files.

  Further provided by the present invention is a set of predetermined printer settings for an inkjet printer, each of which is associated with ejection of various droplet sizes by the printer printhead.

  The invention further includes receiving information about the image printed by the printer, including droplet size information about the required size of the droplets ejected by the nozzles to print the image, Based on determining print parameter information for printing the image and using the print parameter information to set the printer so that the droplets ejected by the nozzle have the required droplet size. And a method for controlling the size of droplets ejected by nozzles of a print head in an inkjet printer.

  The present invention further includes a computer program and a computer program product for performing any of the methods described herein and / or for implementing any of the apparatus features described herein. I will provide a. Also provided is a computer readable medium having stored thereon a program for performing any of the methods described herein and / or for implementing any of the device features described herein. .

  The present invention provides a signal for implementing a computer program for performing any of the methods described herein and / or for implementing any of the apparatus features described herein. And a computer program for performing any of the methods described herein and / or for implementing any of the device features described herein A computer program product having an operating system is also provided.

  The present invention extends substantially to the methods and / or apparatus described in the present invention with reference to the accompanying drawings.

  Any feature in one aspect of the invention may be applied to other aspects of the invention, in appropriate combinations. In particular, method aspects may be applied to apparatus aspects, and vice versa.

  Furthermore, features implemented in hardware may generally be implemented in software and vice versa. References to software and hardware features herein should be construed accordingly.

  The desirable features of the present invention will now be described in detail, by way of example only, with reference to the accompanying drawings.

FIG. 2 is a diagram schematically illustrating a printer control configuration. FIG. 6 schematically illustrates further features of a printer control unit. It is a figure which shows roughly the information processing process in a printer control structure.

  FIG. 1 schematically shows the components of a printer control configuration 1, which are a print head 8 controlled by a printer control unit 3, a raster image processor 5 (RIP), and a print head driver component 9. Includes a printer component 7 that performs printing on a printing material.

  The image data is sent from the image creation / editing device 4 to the RIP 5, for example. The image data input to the RIP 5 may include vector and raster digital image information such as PostScript, PDF, JPG, EPS, TIFF or other image file formats. The RIP 5 may include software that runs on a general purpose or specialized computer, as is well known in the art. For example, such RIP may be based on Wasatch Computer Technology's software RIP adapted to suit this application, as will be described in detail below. In general, the image data input to the RIP is image data converted into bitmap data with a resolution and orientation suitable for transmission to the printer control unit 3. RIP performs not only scaling, rotation, color conversion, and halftoning operations, but also data formatting, and optionally tiling and multiple image layout.

  The image information is then transmitted to the printer control unit 3. The printer control unit in this case includes software executed on a general or professional computer. In this embodiment, the computer that executes the printer control unit software is different from the computer that executes the RIP software. However, these two components can be executed on the same computer. The printer control unit 3 reads the image data sent from the RIP and converts the data into a print instruction sent to the printer component 7 for printing an image using the print head 8. Although the printer component is shown independent of the printer control unit 3 and the RIP 5, one or more other components may be included in the printer.

  In the preferred embodiment of the present invention, the RIP is associated with the droplet size input device 10. For example, the RIP operator may enter the required droplet size data when prompted by RIP software running on the computer. For example, the software may include means for displaying on a computer screen a drop-down list containing various drop size choices that an operator can select. The operator inputs the selection into the RIP, which determines the image data sent to the printer control unit. In a preferred embodiment, the bitmap image data sent to the printer control unit 3 is in the form of an image file in which data relating to the droplet size used for image printing is embedded. The droplet size information is preferably included in the header of the file.

  The image data file is then sent to the printer control unit 3. It will be understood that there is no need for a physical connection between the RIP 5 and the printer control unit 3. For example, the connection may be a wireless connection and / or a network connection, which may include an internet connection. It will also be appreciated that the image information output from the RIP can be loaded onto a data storage medium such as a disk for later loading into the printer control unit 3. Similarly, the connection between the printer control unit and the printer component 7 may not be physical, and the above comment regarding the connection between the RIP and the printer control unit 3 is the same as the printer control unit 3 and the printer component 7. The same applies to the connection between the two.

  FIG. 2 schematically shows further features of the printer control unit 3. The printer control unit 3 includes a processing unit (11) having an input 12 for receiving image information from the RIP 5 and an output 14 for transmitting print parameter information to the printer component for image printing. The printer control unit further includes two memory stores 16 and 18 for storing information used in determining print parameter information. These components of the printer control unit 3 may be provided by a general purpose or specialized computer.

  Referring to FIG. 2, an example of the operation of the printer control unit 3 is described. As described above, the printer control unit 3 receives the print image file transmitted from the RIP 5 at the input 12 and analyzes it at the processing unit 11. The file is first analyzed to determine if it contains data regarding droplet size. If droplet size information is not present, the initial printer settings are retrieved from default memory 18 and used to determine print parameter information for printing the image. The initial printer setting is generally such that the image is printed using an initial or standard drop size (eg, 30 ng drop mass).

  If droplet size information is detected, it is retrieved. The processing unit 11 extracts information from the memory store 16 and uses the extracted information to determine print parameter information for image printing.

  It will be appreciated that the functionality of the two memory stores can be provided by a single component.

  The information retrieved from the memory store 16 or the initial memory store 18 includes information regarding one or more printer settings, values, or printing parameters, the value of which is the size of the droplets ejected from the printer printhead. And / or determine the operation of the printer to be performed with that particular droplet size. In the preferred embodiment, a collection of printer settings is retrieved along with specific droplet size information received with the file.

The printer settings and print parameters may include one or more of the following:
1. 1. Print pulse amplitude 2. Print pulse width 3. Printing pulse voltage 4. Printing pulse frequency Printing pulse timing [For example, when adjustment is required from the viewpoint of time-in-flight of droplets]
6). 6. Operation of the ink amount monitoring device 7. Ink temperature at the print head 8. Relative speed of movement of print head and substrate Printing height (gap)
10. Curing power supply

  It will be appreciated that other settings and parameters may be included.

  The print parameter information may include data regarding settings and / or parameters. This data will be sent to the printer component for use in setting printer settings and / or in determining printer instructions based on image data. Alternatively or additionally, the printer control unit may perform further information processing, or may output a print command to the printer component, for example by outputting a print pulse directly to the print head control unit. good. Thus, some or all of the further processing for determining the print command may be performed in the printer control unit, the printer component, or a combination thereof. Some print parameter information can be used to change the printer settings globally before starting printing (eg, to start operation of the heater unit to change the temperature of the ink in the print head). It may be sent to the printer component before printing begins. Alternatively or additionally, the print parameter information may be transmitted during or after printing.

  Alternatively or additionally, the printer control unit retrieves formulas or other calculated data from the memory 16 and / or 18 to calculate one or more settings and printing parameters. The processor is then configured to calculate the printing parameters using the formula or other data and / or send the formula or other data to the printer component 7 for further calculation.

  When the printer setting is changed from the initial setting for a specific printing operation, the system may be configured so that the setting returns to the initial setting when the printing operation is completed.

  When a new image file is input to the printer control unit 3 and processed, the printer control unit determines whether the printer settings for this printing operation are the same as or different from the current printer settings. If there are no or few changes, some printing parameter information does not need to be sent to the printer components, and some processing at the printer control unit will not be required, thus increasing efficiency. , Thus saving time.

  The determination may be performed by the processing unit 11 that directly analyzes the printer settings to determine the current settings and compares the printer settings required for a particular next printing operation with the current settings.

  Alternatively, or in addition, when determining printer settings required to print a particular image, the processing unit stores information relating to printer settings for printing that image in the setting memory 20 (a component). Stored in memory 16 and / or initial memory 18). Thereafter, when the settings for the next image are calculated, the processing unit 11 retrieves setting information relating to the previous image (which may be expected to correspond to the current printer settings) from the setting memory 20. It has become. The setting information for the previous image is then compared with the setting information for the current image. If some or all of the configuration information is the same, the processing unit determines print parameter information sent to the printer accordingly.

  For configurations where the printer is reset to the default settings after each image is printed, the printer settings comparison is performed to determine whether the current image needs to be changed if necessary. Will be compared to the default setting.

  If information about more than one image is received at a time in the printer control unit, i.e., more than one job is loaded at a time, the printer control unit may in some embodiments print each printed Consider the printer settings required for an image or group of images and determine the print instructions for the print job, preferably to reduce the number of printer setting changes required to print the image It has become.

  Preferably, the printer control unit has a driver for a specific printer. Alternatively or additionally, the printer control unit may be configured to determine print parameter information used for several different printers or printer types.

  For example, the printer control unit can include several memory stores, each containing information about one or more printer settings, or values or printing parameters for another printer. When determining the print parameter information, the information is retrieved from the memory appropriate for the printer for which the print parameter information is intended.

  It will be appreciated that some or all of this functionality may be provided as part of the RIP.

  The determination of information regarding printer parameters and printing parameters associated with various droplet sizes is preferably done experimentally. For a particular printer, various parameters and settings are changed, a test image is printed, and desirable or optimal parameters and settings are determined taking into account image quality, printing speed, and the like.

  It is assumed that two or more of the printer settings and parameter groups are associated with each droplet size. For example, various settings can be made available depending on the required print quality. For example, for a 15 ng drop size, two sets of printer settings can be given. That is, one relates to high quality low speed printing and the other relates to low quality high speed printing. The operator will select which set of settings to use when the print instruction is determined. Alternatively, this selection may be made at the RIP stage. This set of information regarding printer settings and printing parameters may be provided separately by the present invention. This information can be provided, for example, on a data medium loaded into the printer control unit.

  It will be appreciated that RIP 5 can be used to perform some or all operations of the printer control unit and to output print parameter information. However, in this case, since the output of the RIP is specific to a specific printer, such a configuration is not desirable in some cases. However, it should be envisioned that the RIP can be configured to prepare print instructions for a single printer selected from among various printers. RIP and other data processing is performed based on the type of printer specified by the operator.

  Alternatively, RIP can be performed at the printer control unit and / or the printer itself, but this configuration is difficult for high-speed printers because RIP processing can interfere with printing, and therefore an independent RIP is desirable.

  FIG. 3 schematically illustrates the steps performed in an embodiment for processing information in a printer control configuration. In this configuration, the RIP 35 receives various data inputs and outputs a .RTL file 37 to the printer processing unit 33. In this configuration, the printer processing unit includes the VPP 37 and further processing units in the printer components in a printer 39 that includes a printer control unit. In this configuration, the VPP is a program executed on a computer independent of the printer 39. The VPP 37 acquires the output (.RTL file) of the RIP 35 and outputs a print job file (.IPF file 38) to the printer 39 according to the processing steps outlined below. The output of the printer 39 is a print image 41.

  The RIP input 43 includes an image file 45 such as a jpeg or EPS file, information about the required drop mass 47, information about the required image size and resolution 49, color information 51 and the printer mode 53 to be used. These inputs 43 may be input to the RIP 35 via a software user interface of the RIP 35, for example. The RIP 35 converts the data in the image file 45 into an initial print instruction in the form of an .RTL file 36 based on other information inputs 43 including drop mass information 47. The .RTL file 36 includes a header having information including required print resolution, image size, image name, and printer mode in addition to the droplet size information.

  The .RTL file 36 is received by the VPP 37 that executes processing of the .RTL file information. VPP processing is specific to the printer or printer type used for image printing, and the VPP input contains information about the configuration of the printer mode and the print mode used. The VPP 37 analyzes the image data in the .RTL file 36 and assigns all pixels to be printed to a specific printer nozzle of the printer 39. As part of this process, information about the drops to be printed, x and y coordinates are determined. That is, since the .RTL file 36 is not printer specific, it does not contain information about the nozzle configuration used to print the image or other information about the physical layout of the printer.

  The VPP 37 obtains information related to the nozzle configuration of the printer from the PMD file input 55. The VPP 37 then determines which nozzle is used to print each pixel based on the nozzle configuration and print mode.

  The output of the VPP 37 is an .IPF file 38 containing printer specific print instructions for printing an image by the printer 39. Information about the droplet size, as well as other information, is copied from the header of the .RTL file to the header of the .IPF file 38. After being processed by the VPP 37, the .RTL file 36 may be deleted or stored for future use if, for example, the same image is printed again in a different print mode or printhead configuration. (In this case, the information in the .RTL file 36 would be reprocessed by the VPP 37 using another PMD file input 55).

  Thus, the .IPF file 38 has a print job file that is input to the printer 39 to perform printing. In this case, the .IPF file 38 includes not only the carriage position used for each print pass, but also the necessary print resolution, image size, original image name, processing date, use processing parameters, and the like. The file also includes print image data having data relating to image fragments. Each piece is printed on the substrate to be printed by one print head in the print head path, so complete image data is stored in the print head where each print head prints one image piece. Printed by a set.

  The .IPF file 38 is input to a printer where further processing steps are performed and generates a signal to eject droplets from the nozzles of the print head to perform printing of the image 41. As described above, the printer control unit incorporated here as a component of the printer 39 determines the droplet size information contained in the .IPF file 38. The printer control unit then determines the printer settings used to print the image using the particular droplet size in that file 38. All printer settings that need to be changed are changed before the image is printed.

  As shown in FIG. 3, a printer input 61 is provided in the printer. These include, for example, print parameter information such as printer setup information 63, drop mass setup data 65 such as print pulse data for a particular drop size. Also, for example, input of image position information 67 and the like relating to the position of the image of the substrate can be provided. This information may be conveniently stored in a computer memory that is part of or associated with the printer itself, and in particular the printer configuration information is preferably stored in the computer. Alternatively or additionally, for example, some or all of the information may be entered separately by a user using a computer software interface.

  It will be appreciated that other configurations are possible. For example, the function of the VPP 37 may be executed in the printer 39. In fact, the VPP process may be performed in conjunction with other processes in the printer 39 so that a separate .IPF file 38 is not generated. Alternatively, some or all of the VPP processing may be performed by the RIP 35. In this case, .RTL 36 will not be generated.

  Each image file may contain information about printing a single pass using the printer, or it may contain information about printing several passes for the entire substrate being printed. You can leave.

-Drop size determination method-
The droplet size can be determined as follows.
・ Weigh the absorbent pad.
A nozzle for which the droplet size is to be determined or a group of nozzles for which the average droplet size is to be determined is placed adjacent to the water absorbent pad, and a known number of ink droplets are nozzles The print head is jetted so as to be jetted onto the pad.
The pad is weighed again and the number of droplets ejected by each nozzle and the number of nozzles are known so that the average droplet size is determined.

  Accordingly, it will be appreciated that where reference is made herein to droplet size for a group of nozzles, it will be appreciated that reference is made to average droplet size as appropriate.

  Although the present invention has been described above, it is understood that this is by way of example only and that details may be modified within the scope of the present application.

Each feature disclosed in the description and (where appropriate) the claims and drawings may be provided alone or in any appropriate combination.

Claims (23)

In a printer control unit for controlling the size of droplets ejected by the nozzles of the print head in an inkjet printer,
Means for receiving information about the image printed by the printer, including droplet size information about the size of the droplets ejected from the nozzles and needed to print the image;
Means for determining print parameter information for printing the image based on the received droplet size information;
The printer control unit, wherein the print parameter information includes information used to set a printer so that droplets ejected by nozzles during printing of the image have a required droplet size.   The printer of claim 1, further comprising means for transmitting the print parameter information to the printer to configure the printer to print the image using the required droplet size for the nozzle. Controller unit.   The control unit according to claim 1 or 2, wherein the means for determining the print parameter information comprises means for retrieving predetermined print parameter information related to the required droplet size from a memory. .   A control unit according to any preceding claim, wherein the means for determining the print parameter information comprises means for calculating printer settings based on the required droplet size.   The control unit according to claim 1, wherein the print parameter information includes information related to printer settings.   The control unit according to claim 1, wherein the print parameter information includes information regarding a print pulse for ejecting a droplet having the required droplet size from the nozzle.   A control unit according to any preceding claim adapted to control the size of droplets ejected by a plurality of nozzles, wherein the printing parameter information for setting the printer is the image. A control unit including information used to set a plurality of nozzles to eject droplets having the required droplet size during printing.   In the control unit according to any of the preceding claims, adapted to control the size of the droplets ejected by the first nozzle and the second nozzle in the inkjet printer, the droplet size information is Information about two required sizes for the droplets ejected to print the image, wherein the printing parameter information includes the first droplet ejected by the first nozzle during the printing of the image. And includes information used to set the printer so that a droplet ejected by the second nozzle has a second required droplet size. Controller unit.   A control unit according to any preceding claim, further comprising means for determining the printer setting used to print the previous image.   10. The means for determining the printer settings used to print the previous image includes means for comparing the required droplet size information with the droplet size information of the previous image. The control unit described in.   A control unit according to any preceding claim, configured to receive the droplet size information from a raster image processor.   12. A device comprising the control unit according to claim 1 and raster image processor means.   The RIP is adapted to transmit information relating to an image to be printed, the information including droplet size information relating to the size of droplets ejected by a print head to print the image; The apparatus according to claim 12.   14. An apparatus according to claim 12 or claim 13, comprising means for accepting information about droplet size for the printed image in the RIP.   12. The method of claim 1, further comprising: means for determining that droplet size information is not available; and means for determining information relating to an initial setting for printing the image. 15. A control unit according to claim 1 or an apparatus according to any one of claims 12 to 14.   An apparatus according to any preceding claim, further comprising a printer and a printhead configured to receive print parameter information from the control unit.   The RIP is adapted to output information relating to an image to be printed, the information including droplet size information relating to the size of droplets ejected by a print head to print the image; A raster image processor, characterized in that it is preferably used in association with a control unit according to any of the preceding claims.   An image file that contains bitmap information about an image that is printed using an inkjet printer, and further includes information about the droplet size of the droplets ejected by the printer to print the image.   A set of predetermined printer settings for an ink jet printer, each of which is associated with ejection of various droplet sizes by the printer printhead. Receiving information about the image printed by the printer, including droplet size information regarding the required size of the droplets ejected by the nozzles to print the image;
Determining print parameter information for printing the image based on the required droplet size information;
Using the printing parameter information to set the printer so that the droplets ejected by the nozzle have the required droplet size;
A method for controlling the size of droplets ejected by nozzles of a print head in an inkjet printer.   21. The method of claim 20, further comprising transmitting the print parameter information to the printer.   A method substantially as herein described with reference to the drawings.   A method substantially as herein described with reference to and / or shown in the drawings.

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